


SMUTFIC: Good Clean Fun

by TacitlyLeaps



Series: EXPLICIT: Tacit's Lewds, Undertale [1]
Category: Undertale (Video Game)
Genre: Adopted Sibling Incest, Ahegao, Anal Sex, Demon Asriel, Drunk Sex, Edgy Asriel, Erotic magic, F/M, God of Absolute Hyperdeath, Kinky, Kinky sex, M/M, Not good for the SOUL, Other, Perverse Magic, Shower Sex, Smut, Suggest more tags in the comments I am new to this site, Tongue Fetish, Vaginal Sex, WORSHIP!, Write Drunk Edit Sober, gendershifting, smutfic
Language: English
Status: Completed
Published: 2015-12-12
Updated: 2015-12-12
Packaged: 2018-05-06 08:40:48
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,447
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5410289
Author URL: https://archiveofourown.org/users/TacitlyLeaps/pseuds/TacitlyLeaps
Summary: <blockquote class="userstuff">
              <p>The now-adult Frisk and Asriel crash at Monster Kid's place after a night of heavy drinking. Things get weird between Frisk and Asriel, as the latter stumbles in on Frisk having a hangover shower at 4am in the morning, Asriel still drunk and with zero inhibitions. Pair that with an array of lewd, erotic magic and his edgy demon form and you get the weirdest, most perverted explanation on why people are confused about Frisk's gender. </p><p>Also, stupid sexy goat tongue.</p><p>I apologize to the world. WORSHIP!</p><p>You have been warned.</p>
            </blockquote>





	SMUTFIC: Good Clean Fun

**Author's Note:**

> Originally published on /utg/ - Undertale General via Pastebin.

Frisk was being half-carried, half-walked along with the group by Asriel, the big and tipsy goat snickering and chortling along with the rest as they shared amazingly bad puns fueled by the alcohol in their collective systems. Frisk, Asriel and Monster Kid (who still clung to that name, despite all the pressure to have it changed now that he was officially an adult) had been drinking all night, having just left the bar to hit MK's bachelor pad. The armless monster had managed to woo over some human girl, so of course the two of them were very eager to get to the privacy of MK's bedroom. Since he'd promised Az and Frisk a place for the night, the two had to follow along, and hopefully pass out on the couch before they'd get to hear MK going downtown on the lucky girl. 

They were still a few blocks away and Frisk's legs were already giving in, the human having foolishly attempted to out-drink Undyne, whom in turn got some blame for getting the young adult into the drinking contest. Before Frisk could slump down, Asriel scooped them up, huffing and cradling their drunk sibling. His own balance was a bit off, swaying from side to side as he followed MK and his latest catch, but his hold on Frisk never faltered.

Eventually they got to the big apartment building where Monster Kid lived, it never ceasing to amaze Asriel how the guy managed to handle stuff like keys with just his mouth. Guess that's why the ladies loved him. The drunken youth stumbled into the stairway, MK mashing his face against the elevator's buttons. Its doors slid open soon enough, and the four crammed into the lift designed for three max. 

Asriel's back was against the lift's back wall, a nearly passed out Frisk still in his arms, giggling up a storm and nuzzling into his neck fluff. Asriel groaned his disapproval when MK and the girl (whose name Az didn't even know) started to make out as the lift ascended, the goat forced to avert his eyes from the sight to look down at Frisk. They were so cute, even when shitfaced, and a real cuddle-bug, constantly trying to hug and squeeze Az, nosing into whatever bits of fur remained exposed from under his clothes. It totally wasn't weird or anything – they were only adoptive siblings, not blood relatives. 

After what felt like an eternity of awkwardly listening MK sloppily make out with the random girl, the lift finally reached the fifth floor. The troupe of drunks stumbled out of the lift, MK forced to break the obnoxious frenching to dig up his keyring to get the front door open. Again, Asriel couldn't help but give some mental kudos to the champ, who got the door open in a matter of seconds. Without hands, using regular keys. Seriously.

A minute later, Asriel found the couch, slumping down on it and laying Frisk down on the adjacent cushion, head neatly resting against the armrest. He got a few more drunken snickers from their sibling before the human seemed to pass out, Asriel still left awake, sitting there, staring at a black TV screen. He heard MK's bedroom door close, and groaned when very loud, very blatant sounds of slurping followed a minute later. Az weighed his options – either he could dare disrupting his dear sibling's rest to go and find the remote, or try passing out along with Frisk, both options to avoid hearing whatever MK was doing to the girl. 

He reached a paw into the backpack Frisk had been carrying, digging up a half-finished bottle of vodka, grinding a thumb claw through the cap and just tearing it off instead of bothering to unscrew it. Then the goat just started necking it, eager to join Frisk in dreamland.

*** 

Frisk's eyes jerked open near 4 in the morning. Puke was seconds away from bursting out of their mouth, the human leaping up from the couch and making a run for the bathroom. They could hear Asriel slumping down onto his side in the now vacant spot Frisk'd left, their brother snoring nearly as loudly as their Winnebago-of-a-dad did. 

Memories of Undyne's shit-eating grin flashed through Frisk's head as they dropped to their knees in front of the toilet, hunching over the ceramic bowl, whole body convulsing as it purged itself from mixed drinks and shitty bar food mixed with stomach acids. It wasn't a pretty sight, but at least Frisk got all of it into the toilet. Even now, they were determined not to fuck things up. 

After something like a quarter hour of coughing up watery, technicolor slop, nothing more came up, leaving Frisk shaking and shuddering from weakness. It felt like someone was taking a sledgehammer to their skull, the human standing up with trembling legs, wiping a stray streak of drool onto the sleeve of their shirt. Then Frisk's eyes noticed the shower booth, and before thinking about it any deeper, the human started to discard their clothes and climb into the shower. Right now, nothing felt more appealing than a hot, steamy shower to curl up in. 

Frisk stepped into the shower, fully nude, yanking the tap's handle. Ice cold water splashed all over them, making Frisk unleash a string of curses that would have made Toriel immolate the human on the spot. Frisk kept snarling out all kinds of filth for a few more seconds before the water turned warm, then hot, the cussing fading and ending with a relieved sigh. The shaking human remained standing for couple more minutes before just sitting down on the tile floor, letting the steamy, hot water cascade over them. 

Time began to lose its meaning. Frisk sat there, knees pressed against their chest, water drumming the top of their head and splattering soothingly on the hard floor around them. The humid heat comforting Frisk, the human slipping into a bit of a trance…

...Which was only broken when Frisk realized that someone else was in the bathroom. Damnit, they'd forgotten to lock the door on their way in. Leaning their head out of the glass-paneled stall, Frisk checked who was using the toilet. It was none other than their brother, Asriel.

The goat was standing in front of the toilet, jeans and underwear by their ankles, the tall guy swaying back and forth as he pissed in the bowl. He had a drunk, dopey grin on his muzzle, several inches of broad, pink tongue lolling past the side of his maw, not even checking if the stream was hitting its mark, half-hard dick held between two fuzzy fingers. Judging by the sounds Frisk heard, Az' aim was clearly off. 

Before Frisk could hide their head back behind the foggy glass, Asriel noticed them. The dumb, drunk grin on his face got wider, and he took a stumbling step towards the shower, leaving the bundled jeans and boxers behind. “Brotherrr!” the goat bellowed in drunken stupor, cramming himself into the shower booth before Frisk could do as much as stand up and close the stall's sliding door. 

“Fuck off, Az!” Frisk snapped, the both of them bumbling about in the booth resulting in loud thunks amidst the splashing water. Asriel was still wearing his t-shirt, which got soaked just as fast as his fluffy fur, but that didn't break his stride. The human was in no mood to put up with Asriel's drunken acts, honestly just wanting to stay curled up and meditating until the headache would go away. 

“Frrriiiisk, chill.” Asriel chortled, pulling Frisk into a way too strong hug. That wasn't actually the worst part of it for Frisk, the crushing tightness of the hug, rather it was the fact that Frisk was fully nude himself, and Asriel was nude from the bottom down. Frisk blushed furiously, fidgeting in the hug before he realized it was making it worse, the human male's junk rubbing right against the side of Asriel's sheath. 

If Frisk played his cards right, maybe Az would be content with just hugging him for a couple minutes and then bugger off back to the couch to pass out. All he had to do was stay perfectly motionless and not get the goat riled up…  
...Which was too late. Frisk could feel Az' furry sheath twitch and throb against the side of his flaccid shaft. His eyes slowly trailed up from Asriel's wet, shirt-covered chest, seeing a big, lecherous grin on the goat's face.

“...No!” Frisk snapped again, a stern but flushed look on his face. Asriel's blatantly horny grin was just getting wider, and he started to grind his hips against Frisk's. “C'mon, Az, go sleep it off.” He continued, standing on his tiptoes long enough to boop his nose against Asriel's snoot. Maybe an offering of snootleboops could ward off the horny goat?

No such luck. Black, tattoo-like, streaks started to appear on Asriel's cheeks. The sclera of his eyes turned black, his rises becoming pure white slits. 

Great. He was putting his edgy demon persona on. Something he only did when things were about to get really, really weird between the two of them. 

The human rolled his eyes while Asriel peeled off the sodden shirt, throwing it onto the pile of Frisk's clothes. The black, symmetrical, markings were spreading around the goat's body, Frisk's skin feeling tingly as magic built up in the air like static electricity. 'Oh well, no stopping him now', Frisk thought, sighing and smirking as he laid his hands on his brother's matted hips, caressing the fur there briefly before his fingers trailed behind Az, stroking along his lower back. 'Might just as well try to enjoy it.'

“Urah ha ha… Not very determined to put up a fight tonight, huh?” Asriel rumbled, still grinning, seeming surprisingly sober all of the sudden. Frisk reckoned he was either using magic to clear his thoughts or then the magic was using the drink as fuel, or something like that. Asriel's inner workings were a persistent enigma, and the human, who's head was still hurting, didn't want to dwell on that any longer. With a defeated sigh, Frisk just stood up on tiptoes again, giving Az a short-but-sweet kiss right on the lips. 

“Isn't that delicious? Thinking you can appease the God of Absolute Hyperdeath with such weak worship?” Asriel was power tripping now, complete with cringeworthy dialogue, levitating half an inch off the ground and nearly doing the Exorcist headspin before Frisk grabbed him by his horns to stop him. “Tone it down Az, you're either gonna wake MK up, or break something, or both.” 

Instead of that, Asriel's black eyes just widened with glee, maw in an open grin, looking like he was going to launch into loud, cringeworthy gloating, possibly with magical stars and rainbows blasting around and breaking everything in the bathroom. Frisk squeezed his fingers tighter around Asriel's grooved horns and then pulled on them as if they were handles to force him into a kiss to shut him up. 

A lustful, muffled growl rumbled from Az' throat, the goat tilting his head and deepening the kiss. One arm wrapped around Frisk's back, one hand taking a gentle hold of the back of the human's head, dark claws lightly pricking the smooth, soft skin. Frisk's fingers slipped away from his brother's horns, trailing down along his neck, sifting through the soaked fur. He could feel the normally fluffy fur change around his fingers, becoming silky with an almost oily surface, impossible for water to penetrate. After all, a proper demonic goat prince couldn't go around with their fur matted, even whilst in a steaming hot shower.

Frisk closed his eyes, embracing the passionate, if taboo, moment. It felt more soothing than arousing, given the persistent headache, his hands wandering over Az' back, feeling the fine muscles hidden under the soft fur, his body feeling so enticingly warm. Frisk couldn't help himself, pressing against Asriel, trying to snuggle with the tall, warm goat.

Asriel saw that Frisk was getting far too comfortable, a mischievous glint in his monochrome eyes. His jaws parted ever so slightly in the kiss, trying to goad Frisk into doing the same. The human fell for it, and realized his mistake too late, eyes going wide from the realization. There was something particularly weird Asriel always did if the kiss got passionate enough, and Frisk hated himself for falling for it every time, even more the fact that he loved it.

The demonic caprine's thick tongue outright plunged into Frisk's mouth, dragging over the roof his his mouth, trapping the human's tongue under it. Shivers went down Frisk's spine as that hot, slimy appendage felt around in his mouth, a dark blush flashing onto his cheeks, fingers gripping tufts of Asriel's backfur between them, his own down pathetically wriggling under the broad, thick goat tongue. Asriel's eyes were gleaming with perverse delight from seeing his brother uncomfortable like that, Frisk feeling his swollen sheath throb lewdly against his smooth-skinned belly. There was a bit of sadist in Asriel, and a bunch of masochist in Frisk. 

From experience, Frisk knew having his mouth full of goat tongue was only the start of it, shaking his head with the hopes that maybe Az would spare him. Az simply chuckled in response, tongue ominously inching towards Frisk's throat. He kept shaking his head, Asriel nodding his, and then the thick, squirmy tongue began to slide down the human's throat, gag reflex kicking in. Frisk's hand weakly batted Asriel's side, the other grabbing his horn, a muffled moan rising from his violated throat. That tongue was gradually worming its way deeper, Frisk feeling it flex and wriggle as it pushed down his esophagus, his throat clenching and convulsing around it. And yet… He liked it, in some weird, masochistic, fashion. Feeling his brother take control, toying with Frisk's body, the human seeing and feeling the pleasure Az got from it… 

Frisk would have put up a real fight, since he knew Az loved it when he got uppity, but his muscles were sore and aching from the hangover, and with the pounding headache he couldn't even get more than half-hard, even as Asriel's warm, furry hips brushed and rubbed flat against his groin. In stark contrast, Az' shaft was proudly jutting out from its furry sheath, resting against Frisk's abdomen, the tip nearly reaching the human's chest, precum oozing out and getting washed away by the steaming, splashing water. Asriel was hung as a horse, and with all the magic he had in store, well… Frisk's legs felt weak from the memory of a few very, very intense sessions. 

Frisk was like putty in his demonic-looking brother's arms, that invading tongue bulging his throat, harsh shivers coursing down the human's back, semi-hard manhood twitching and pulsing as it desperately tried to get fully erect. He was starting to think that Asriel was at least partially behind him staying so soft, using some of that excessive magic to to prevent him from getting hard, probably to tease and taunt Frisk even further. One of the goat's hands slid down along Frisk's back, claws tracing over that twitching spine until the claw-capped fingers reached his rump, giving the plump cheeks a possessive, lustful grope.

The tongue lodged deep inside Frisk reeled, the feeling of it slithering out getting nearly as much deranged, perverted pleasure out of him as it felt going in. A soft gasp escaped his mouth the moment Asriel's lips and tongue pulled away, Frisk panting softly for air, mixed drool leaking down his chin. Az' horny grin went from ear to ear, the goat licking and smacking his lips lewdly, bucking his hips suggestively. Frisk didn't protest – half-hard dick twitching and dripping with pre, he turned around, bending over and placing his arms against the wall, presenting his smooth-skinned, plump ass to his brother. 

And the demonic goat eagerly accepted the offering. His hands grabbed Frisk's hips tightly, claws pressing harshly against the unblemished, silky skin, a deep, lustful groan-bleat reaching Frisk's ears through the steady drumming of the cascading water. His back arched as he felt Asriel's hard, twitching cock slide between his bared asscheeks, that roughly 10-inch monster throbbing powerfully, jetting streaks of pre across Frisk's back, which lingered there for some seconds before being washed away. 

Frisk was mustering the strength to say something, but whatever words he had prepared came out as a excited, pleasured, moan, Az' tip pressing against Frisk's pucker, excessive amounts of hot, slimy pre pooling onto it. Honoring Frisk's implied wish to stay silent, Asriel reached a hand out to grab Frisk's face, holding his mouth shut, sliding a single finger into their brother's mouth. “No biting, or you know what happens, brother.” Asriel whispered, sharply thrusting his hips, grunting in bliss as the first inch of his rock-hard, constantly throbbing shaft sunk into Frisk's ass.

Frisk was fighting not to bite down on Az' finger, whole body trembling from the effort as that thick, hard manhood pressed deeper, stretching the muscles, grinding against the human's inner flesh. He clenched his eyes shut, trying to stifle all the moans welling up in his chest, whatever sounds slipped out ending up muffled by Asriel's hand. The demonic goat forced more of his dick inside with short, sharp thrusts, giving Frisk close to no time to adjust, nudging and pressing against all the right spots inside of him to force the human's muscles clench and squeeze around his pre-sputtering shaft. 

Once only a third of that pulsing, amazingly hot shaft remained outside Frisk's ass, Asriel hilted inside his brother with a mighty slam of his hips, his heavy, furry balls slapping against the human's. This time around, he gave Frisk time to adjust, the goat groaning in delight as those hot and tight inner passages rippled around his dick. The contractions only got more intense as Az angled himself a bit better, grinding his shaft right against Frisk's prostate, it making the bent-over human outright squeal in bliss, whole body tensing and shaking, a heavy drool of pre lazily oozing out of his still half-hard shaft, dripping onto the tile floor, amidst all the water.

After enjoying watching his human brother squirm and moan for a while, Asriel pulled back, sliding out until only the tip of his shaft remained inside the twitching, puckered, hole. Then he started to ram it all back in, this time grinding in smoothly, groaning as he buried his entire length in with a wet, slimy 'shuk' thanks to the excessive amounts of pre lubing him up, hips lewdly smacking against Frisk's ass. “Nnngh, brotherrr...” 

Asriel worked himself into a rhythm, thrusting deep into Frisk with every slam of his hips, hunching over the human as he pistoned into him like a lustful beast. Frisk shook from the force of each harsh thrust, jaw trembling as he kept fighting against the urge to gnaw his brother's finger, muffled moans constantly rising past the furry hand. He panted loudly through his nose, shivers running down his back every other second from both the intense pleasure of Az' cock reaching in deep and the goat's heated, humid breath blasting against his neck, able to feel it even through all the crashing, steaming hot water. 

Time began to lose its meaning again as Frisk's head swam in pleasure, it nearly drowning out the sharp headache from his hangover. Face ablaze with a blush from all of it, panting haphazardly against his brother's paw, eyes rolling back in their sockets. Asriel was taking his time in enjoying his brother, shaft sliding inside with ease thanks to all the pre he'd been pumping out nearly non-stop, Frisk's hips starting to feel numb from the relentless pounding. The human had been losing ground steadily, ending up more and more against the tiled wall with each passing minute, right up until he was flat against it, squirming out of instinct while the hung goat demon used him. Trying to stay quiet had long since slipped from their minds, Asriel grunting and groaning rather loudly, hips slamming against Frisk's rear with enough force to send deep thuds reverberating through the wall. 

Frisk felt a familiar pressure build up deep in his groin, the still half-hard shaft twitching pettily, spurting wads of sticky pre onto the humid wall. A moment later, Frisk gasped sharply as he started to cum, making his hips twitch and buck weakly, a few streaks of spunk squirting onto the tiles. The effects were felt much stronger inside him, muscles deep within his hips clenching and tensing intensely as the human shot out his load, finally losing control and accidentally biting down on Az' finger that had been stuffing his mouth the whole time. 

That seemed to be a trigger of some sort of Asriel, Frisk's eyes going wide as his brother started to really jackhammer his ass, the tall demonic goat huffing and grunting bestially, using a punishing amount of force in his hard, fast thrusts, the whole booth shuddering from the fierce impacts. Frisk tried to cry out, Az stuffing two more fingers down his mouth to keep him from doing so, and with one final, ferocious slam of his hips, Asriel buried himself balls deep into Frisk's ass, barely keeping himself from letting out a bellowing moan by biting onto Frisk's shoulder. That large, achingly hard cock throbbed angrily against Frisk's inner walls, erupting into a massive torrent of thick and hot goat spunk. It came out in huge gushes, a single one of them easily drowning out whatever little Frisk had managed to pump out, the human feeling that liquid heat fill up his belly. Az was naturally hung and productive, and he'd no doubt used his perverted magic to enhance that even further, giving Frisk a heavy, creamy filling. 

It took over a minute for Az' climax to taper off, his jaws finally dislodging from around Frisk's shoulder, the goat covered with black markings huffing and panting for air, dick still twitching heavily inside his brother's cream-filled ass. His teeth had left red marks on Frisk's skin, but only the two spots where his fangs had sunk in had drawn blood, two thin trickles of it running down Frisk's chest.

“Wow…. You really are something special, brother.” Asriel whispered with a sly chuckle, hand finally sliding off from Frisk's face, grabbing his chin instead and turning his head so that he could fully appreciate the look of ahegao. His human brother's skin was flushed in a lot of places, but those cheeks were like two red beacons, a quarter inch of tongue hanging out past his lower lip, the male drawing in deep, wavering breaths, sharp and sudden shudders still coursing through his slender frame. Frisk couldn't feel his legs by now, more or less held standing upright by his brother's still-hard dick. 

In fact, Frisk felt exhausted, both from the hangover and the dicking of a lifetime that he'd just gotten. He almost drifted to sleep on the spot, if it hadn't been for Asriel nipping his neck, sending a refreshing jolt of pain through him, Frisk gasping and feeling a lot more awake. He shot Az a stern, frustrated look, which was hard to pull off with how flushed he was.

“Oh, did you think I was done, brother? Urah ha ha...” 

Frisk groaned tiredly, fidgeting with whatever little strength he had left in his muscles. He really wanted to go and pass out on the couch now, preferably while held tightly in Asriel's arms. His belly was so full of the goat's release that it was pudging out ever so slightly, the sense of heat spreading to his muscles from the still-hot cum feeling amazingly relaxing. The alertness from the nip was rapidly fading, Frisk starting to drift off again…

...Only to get nipped again! Az was really starting to piss him off, clearly having overstayed his welcome in Frisk. Mustering some good old determination, Frisk was tried to put up some resistance, strength returning to his muscles…

...And then it stopped, power slipping away from him, the human slumping. The determination he had conjured up had been sapped by two sparks of magic the Az' nips had left in his body. 

“At… my most vulnerable moment…!” Frisk managed to groan out, rolling his eyes and giving Asriel an exaggerated look of shock. He knew he wasn't in any danger – at worst, he'd just have to endure whatever perversions his demon-form brother still wanted to enact on his defenseless body. 

Asriel wasn't doing anything but staring at him with a sly, lewd, open-maw grin, a perverted glint in those black eyes. Frisk groaned as he felt magical heat build up in his neck, right where Az had nipped him, before it suddenly exploded, jolting out to every limb of his body, making him twitch and squirm involuntarily. “Fff- Az! What the ssh-” 

Frisk froze, suddenly realizing what was gonna happen, eyes wide. Very familiar magic was spreading around his body, an exotic warmth and tingling settling into his muscles and flesh, his chest and groin becoming hotspots for the energies. He hadn't actually expected that drunk Asriel could pull a spell this complex off, looking over his shoulder at Asriel again, a wide-eyed, genuinely shocked look on his flushed face. “Oh, no, you didn't...”

“If my brother couldn't truly satisfy me tonight… Maybe my sister can, hmm?” Asriel's voice was dripping with slyness and lust.

Frisk bit his lower lip as his brother's perverted spell really got to work, the gaunt, masculine shapes of his body starting to round and turn soft. Hips growing wider, thighs thickening while the rest of legs slimmed out some, chest starting to slowly bloom outward as breasts began to form. Once again, shivers were running through the changing human's body, dainty fingers clenching into fists, knees nearly buckling as he was becoming more and more feminine. He broke into panting, hearing the masculine tone of his voice shifting to a more feminine pitch, fighting to keep himself from moaning mid-change, to at least deny his brother that much. 

Almost as if sensing that Frisk was holding back on him, Asriel moved a hand down to the shifting human's groin, fingers teasing his diminishing manhood by flicking and rubbing it. Already, everything felt far, far more sensitive down there, Frisk biting his lower lip, reflexively pressing his hips against Asriel's fuzzy digits, a girly moan finally escaping him. It made Asriel chuckle with perverse delight, rewarding Frisk with a long, wet, lick across his neck, trailing down his spine. Soon the last evidence of Frisk ever being a man had disappeared, a pair of sensitive, puffy slitlips on his groin, the human moaning again as he felt a new passage opening deep into his body, the new muscles and flesh surrounding it already quivering, moisture beading in the narrow gap between the swollen, reddened lips. The demonic goat's fingertips trailed over the smooth, slightly slickened skin, sending erotic tingles deep into Frisk's core. 

Asriel inhaled deeply, groaning lustfully as his nose picked up the new, feminine, scent rising from Frisk. It was safe to say that she was his sister again, for the first time in a few months. This was far from being the first time Asriel had toyed with Frisk's body to that extent, and it certainly wouldn't be the last. 

“Grrnh, I've missed this… You have such a lovely, irresistible scent, dear sister...” The still horny goat rumbled, Frisk feeling Az' rock-hard shaft twitch excitedly inside of her rump. With a single hard tug, her brother pulled out, making her gasp and tremble as that 10-inch beast left her gaping, excess cum leaking out of that much-abused ass, the shower washing it away like it had done with most things. Asriel took a step back from Frisk, hands trailing to her hips, feeling them over, surveying his perverse, magical, handiwork. He hadn't gone overboard with Frisk's new assets; very, very fine and supple for a woman her age, but still within the limits of reason. After all, if he made her too voluptuous, it would raise even more suspicion and confusion about Frisk's gender, not to mention that Frisk hadn't packed any clothes that would comfortably fit her. It'd be an awkward walk home the next morning, if Frisk could even walk in the first place after all the love and attention Az had given her backside.

“C-c'mon, Az, let's just go rest...” Frisk softly pleaded as she was spun around by her brother, back against the wall now, biting her lip as Asriel reached a hand to cup her breasts. A fine, seemingly natural C-cup, and probably more sensitive than they should be, the female squirming and stifling a moan as Az fondled the perky tit, rubbing a thumb against the nipple. She swore that Asriel always made her more private parts overly sensitive, just so that he could get a quick reaction out of her whenever he was feeling particularly mischievous. Fresh arousal was already building up in Frisk, simply from the pleasure of the change and from having Az feel over her soft, feminine form. 

Az responded to her request by suddenly grabbing her, lifting her a few inches up on the wall until the changed human was eye-level with him, the goat kissing her deeply. At the same time, she could feel Asriel's cock brush against her brand new pussy, a buck of his hips quickly forcing the tip inside the moist slit. Once again, her eyes went wide, her whole face burning up with a bright blush, a shuddering moan pressing into the passionate kiss as jolts of ecstasy surged through her body. Frisk's toes curled up, cunny clenching around her brother's invading shaft, a messy trickle of fluids flowing out from her depths. Frisk couldn't help but admit that she loved being a sister, waves of pleasure washing over her sleek, curvy form, her hands wrapping around Asriel's back, gripping tufts of fur for support.

Demon Asriel cherished every last moment of feeling his beloved sister squirm and shudder against his body, loving the little moans that were muffled by the kiss, the smell of her arousal and sweat driving him wild. Powerful squirts of pre surged deep into Frisk's cunny, the goat easing his cock in with tormenting slowness, the hot, velvety folds of flesh convulsing harder and faster the deeper he reached. To add to her sensory overload, he pressed his tongue against Frisk's lips, trying to wriggle it into her mouth, the human falling for it as she always did, the long, thick tongue darting into her. A second later, it was invading her throat, Frisk's eyes twitching and then rolling back, the human lifting and throwing her legs around Asriel's waist. She was completely lost to her carnal lusts, mouth and throat plain sucking on Az' tongue instead of trying to force it out, the tight, nectar-oozing vent between her legs instinctively trying to milk his fiercely throbbing manhood. 

Asriel was starting to lose control just as much, grunting as he savagely ground his pulsing shaft all the way into Frisk. He couldn't stop himself from pulling out a second later, only to slam right back in, a burst of his and Frisk's mixed fluids gushing out of the stuffed slit with the lewdest squelch. The demonic caprine started to rut with Frisk like a feral beast, grunting and huffing as he pistoned his hips over and over, deep thuds resonating through the walls. Frisk's nethers frantically convulsed around Az' raging hard, violently throbbing dick, a perverse bulge appearing in her still pudgy belly whenever he was all the way in, her arms and legs squeezing harder around her brother's back as she was pounded like no tomorrow. 

Frisk was the first to cum, nerves nearly fried from the wracking pleasure of Az' large cock plunging into her relentlessly and the exotic, depraved bliss of that meaty tongue stuffing her throat being too much for her altered, overexcited body to handle. Her fingers tried to dig into Asriel's skin, a broken and muffled scream rising from her blocked throat as her pussy first clamped, then quivered rhythmically, girlcum violently squirting out. Asriel wasn't far behind, hilting into Frisk with a brutal thrust that sent her further up the wall, a bleat of pleasure pushing through the depraved kiss as he started to pump her full of thick goat cum. She could feel Asriel's heartbeat through that furiously throbbing and twitching shaft, her already cum-packed abdomen only getting more bloated as her womb was filled up with a fresh load of potent caprine seed. Luckily for the both of them, Az' magic had skipped on making her body fertile, preventing a huge disaster that would have ensued otherwise.

Her orgasm was too intense on her already so much abused body, Frisk's eyes closing, panting erratically through her nose, everything below the waist completely numb. She rapidly slipped into deep sleep, still pinned against the wall by Asriel, who didn't zap her with revitalizing magic this time around. The last thing she felt before drifting off to dreams was her heart pounding in her ears, Az' thick shaft pulsing heavily deep within her, his tongue wriggling lewdly in her throat, his furry body feeling so very warm against her skin… 

*** 

Frisk woke up slowly, yawning widely, opening her eyes before squinting them as light hit them. Her head was still pounding some, eyes feeling sore. She started to pick up other sensations from around her body as the seconds passed – noticing that she had breasts now, a warm, gooey filling weighing her belly, legs staying half-asleep while the rest of her body woke up. Her hips felt sore, but it was a pleasant, comfy soreness, Frisk had to admit. 

Then the memories, both spotty and clear ones, from last night began to flash through her mind. She hissed and sat up, patting herself over just to confirm that she was, indeed, wearing clothes. Her sweater and jeans felt a bit damp, and a memory of Asriel throwing his soaked shirt onto the pile of her clothes returned to her. Great

It felt weird not having any bra on under her sweater and undershirt, lamenting the fact that Asriel didn't know any magic that could conjure up clothing. She'd have to nag about it to him, since if he could change her gender like it was just flicking a switch, while shitfaced, he damn well should be able to find a way to get her some dry and fitting clothes. Oh well, maybe no one would catch onto it before they'd get home.

Speaking of Asriel, Frisk couldn't see him anywhere in the living room. She could pick up his scent, her brother clearly having remained cuddled up next to her through the rest of the night and the morning, the human grumbling that he hadn't had the common decency to stay with her until she was up. After double-checking that her clothes were in order, Frisk got up, heading for the kitchen for something to drink. Her legs felt a little weak, and she considered asking Az to carry her all the way to the bus stop. It was the least he could do, after last night. 

She was pleasantly surprised to find her brother sitting by the kitchen table, along with Monster Kid, the two drinking coffee and chitchatting. She found herself an empty glass, filling it water from the tap, after which she turned around and leaned plump butt against the counter, facing the two guys. MK had stopped talking, staring at her with a puzzled expression.

“Morning, Frisk!” Asriel smiled, a light blush showing through his cheek fur. He looked as normal as ever, fur all fluffy and lacking the demonic black markings, a sheepish smile on his face. Looking rather guilty, actually. “Yo.” Monster Kid commented before returning his coffee, drinking it from a straw. No hands, and all that. 

A moment passed in silence, MK just switching between staring at the guilty-looking Asriel and unamused Frisk while sucking coffee through a straw, and just when he looked like he was about to ask something, Frisk interrupted, trying to divert attention from her. “Had fun last night, huh? Did'chu get her number?”

Monster Kid looked stunned, blinking a few times before beaming, nodding his head. Asriel joined Frisk in diverting his attention from the two of them, getting MK to start talking about all the fun he'd had with the girl. The details went into the TMI territory real fast, Az and Frisk even faking surprised and slightly disgusted looks at a few points, but kept goading the lizard on. 

They ended up spending a couple more hours at MK's place, talking about this and that, recovering from their collective hangovers and cleaning the place up, promising to pay most of his next month's water bill and agreeing to pay to have a cracked glass panel in the shower stall replaced, both of them denying to ever actually using the shower. Well, Frisk told that she'd forgotten the shower on for an hour or two and had actually only used it for a few minutes, while Asriel had totally been sleeping the booze off on the couch the whole night. This hadn't been the first time they'd tried to cover their asses, and since both of them were good-natured people, they always did pay for any damages they had caused, whether they admitted being the cause or not. After all, Az was related to royalty, so money never was a problem.

After everything was done, the two said their goodbyes to Monster Kid and left for home. Asriel even agreed to carry Frisk in his arms like the dork he was, not even conscious of how silly it looked as he walked with Frisk in his arms like a bride, the human nuzzling into his neck fur with a floppy goat ear over her head to shield her from the sun. Once they got home, Toriel didn't even notice that there as anything off about Frisk. She had learned not to try gendering her adopted child a long time ago, as had most of Frisk's friends, especially after she'd acted all offended whenever someone tried to pry any further. For now, what she and Asriel had between them would remain a well-kept secret, which only strengthened the weird-but-loving bond between the Fallen Human and the Prince.

**Author's Note:**

> /utg/ and cheap liquor are responsible for this mess. Also, shout-out to my main man Motif who did some editing work. Yes, I subjected that poor soul to my unfiltered filth.


End file.
